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  • 毒品和神经系统

    Is coffee a drug ?
    ::咖啡是毒品吗?

    Maybe. But that doesn't necessarily mean it is bad for you. Many people drink a cup of coffee each morning to help them wake up because the caffeine in coffee stimulates the . Coffee is one of the milder drugs affecting the .
    ::很多人每天早上喝咖啡来帮助他们醒来, 因为咖啡中的咖啡因刺激了咖啡。咖啡是影响咖啡的较温和的药物之一。

    Drugs and the Nervous System
    ::毒品和神经系统

    A drug is any chemical or biological substance that affects the body’s structure or functions. Drugs in the form of medicines are used to treat many illnesses and disorders. A medicine (or medication) is a drug that is taken to cure or reduce the symptoms of an illness. However, drugs, whether they are medicines, legal, or illegal drugs, can be abused for the effects they have on the central nervous system (CNS). In fact, many medical uses of drugs depend on the powerful effects they have on brain function. For example, anti-depression medicines are used to treat depression and anxiety disorders, and anti-psychotic medicines are used to treat schizophrenia and bipolar disorder.
    ::一种药物是影响身体结构或功能的任何化学或生物物质; 药物形式的药物用于治疗许多疾病和疾病; 药物(或药物)是治疗或减少疾病症状的药物; 但是,药物,无论是药物、合法药物还是非法药物,都可以因对中枢神经系统的影响而被滥用。 事实上,药物的许多医疗用途取决于其对大脑功能的强大影响。 比如,抗抑郁药物被用于治疗抑郁症和焦虑症,而抗精神病药物被用于治疗精神分裂症和双极紊乱。

    A psychoactive drug is a substance that affects the central nervous system by altering cognitive function. Changes in cognitive function result in changes in how a person feels, thinks, perceives, and acts. Almost everyone has used a psychoactive drug at some time in their life, and many people take such drugs daily. For example, the coffee or tea that you may have drank to waken yourself up this morning or the cola, energy drink, or chocolate that you had as a snack all contain the psychoactive drug caffeine. Caffeine is a CNS stimulant that makes you feel less drowsy and more alert. Coffee beans, the most common source of caffeine, are shown in Figure .
    ::精神活性药物是一种物质,通过改变认知功能影响中枢神经系统。认知功能的变化导致一个人的感受、思考、感知和行动方式的改变。几乎每个人都在生活中的某个时候使用精神活性药物,许多人每天服用这种药物。例如,你可能喝咖啡或茶来唤醒自己今天上午的咖啡或茶,或者你作为零食的可乐、能量饮料或巧克力都含有精神活性药物咖啡因。咖啡因是一种CNS兴奋剂,它让你感到不那么晕眩,而且更加警觉。咖啡豆是咖啡因的最常见来源,在图中显示。

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    Roasted coffee beans. Coffee beans are a common source of the stimulant caffeine. Other plant sources include the leaves of tea, cocoa, yerba mate, and guarana plants. These plants use caffeine as a means of protection against being eaten. The caffeine in the leaves of these plants can paralyze and kill the insects that feed upon them.
    ::烤咖啡豆; 咖啡豆是兴奋剂咖啡因的常见来源; 其他植物来源包括茶叶、可可、麦芽叶和瓜拉那植物。 这些植物使用咖啡因作为防止被吃掉的手段。 这些植物叶上的咖啡因可以瘫痪并杀死养活它们的昆虫。

    Product Caffeine Content (mg)
    Coffee (8 oz) 130
    Tea (8 oz) 55
    Cola (8 oz) 25
    Coffee ice cream (8 oz) 60
    Hot cocoa (8 oz) 10
    Dark chocolate candy (1.5 oz) 30

    Drugs and the Brain: How Psychoactive Drugs Work
    ::药物和大脑:精神活性药物如何工作

    How we perceive and respond to stimuli is a result of sending action potentials and neurotransmitters to both each other and other in the body. Psychoactive drugs affect how neurons communicate with each other. These drug molecules can alter neurotransmission by blocking receptor proteins , mimicking neurotransmitters, or changing the amount of neurotransmitters in a , as shown in  Figure , by blocking reuptake. In this way, a psychoactive drug can change how we feel, think, and interact with the world. Sometimes these effects are beneficial, such as taking a prescribed painkiller (hydrocodone, for example) to ease the pain of a broken . Sometimes the effects are harmful, which could happen if the person continued to take the powerful painkiller long after their broken bone had healed. Some examples of psychoactive medicines are listed in  Table .
    ::精神活性药物影响神经元相互交流的方式。这些药物分子可以通过屏蔽受体蛋白、模仿神经传导器,或者通过屏蔽重验来改变神经传导器在一种神经传导器中的含量,如图中所示。通过这种方式,精神活性药物可以改变我们的感受、思考和与世界互动。有时这些效果是有益的,比如服用处方止痛药(例如氢可酮)来缓解破裂的痛苦。有时,这些效应是有害的,如果一个人在骨折后长时间继续服用强力止痛药,就会发生。一些精神活性药物的例子列在表格中。

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    The release of neurotransmitters into the synaptic cleft. Depending on its method of action, a psychoactive substance may block the receptors on the postsynaptic neuron, block reuptake, or affect neurotransmitter synthesis in the presynaptic neuron.
    ::神经传导器释放到神经元裂缝中。根据其行动方法,精神活性物质可能会阻塞后合成神经元的受体、块状重新摄取,或者影响前合成神经元中的神经感应合成。

    Some Psychoactive Medicines and Their Uses
    Type Uses Example Action
    Anesthetics Block pain and other sensations. Often induce unconsciousness, which allows patients to undergo medical procedures. Lidocaine and nitrous oxide. Mimic the inhibitory neurotransmitter GABA or increase the amount of GABA in the synapse, which prevents an action potential .
    Painkillers (analgesics) Reduce the sensation of pain. Includes narcotics and non-steroidal anti-inflammatory drugs (NSAIDS).
    Narcotics: morphine and codeine.
    NSAIDS: aspirin and acetaminophen (paracetamol).
    		Drug molecules mimic endogenous opioids (“natural painkillers”), such as endorphins, by binding to opioid receptors.
    Antidepressants Antidepressants are used to treat disorders such as clinical depression, anxiety, and . Selective Serotonin Reuptake Inhibitors (SSRIs) and Monoamine oxidase inhibitors (MAOIs).

    SSRIs: Block the uptake of the neurotransmitter serotonin by the presynaptic neuron. MAOIs: Prevent an from breaking down serotonin in the synapse. Both actions result in an increase of serotonin in the synapse.
    ::SSI: 阻止先天性神经神经元吸收神经分质血清素。 MAOIS: 防止神经突触中的血清素分解。 这两种行动都导致神经突触中的血清素增加。

    Stimulants Used to treat disorders such as attention deficit disorder and to suppress the appetite. Amphetamine salts. Increases extracellular levels of dopamine, norepinephrine, and serotonin by various means.
    Antipsychotics Used to treat psychoses such as schizophrenia and mania. Chlorpromazine. Blocks dopamine receptors in postsynaptic neurons.
    Cough medicines (antitussives). Used to treat persistent coughing. Dextromethorphan (DXM) and codeine. Inhibits the action of the NMDA receptor in the postsynaptic cell. Reduces action potentials and is similar in action to anesthetics.

    Drug Abuse
    ::药物滥用

    Psychoactive drugs bring about changes in mood and feelings that a user may find desirable; therefore, many psychoactive substances are abused. Drug abuse is the repeated use of a drug without advice or guidance of a medical professional or use for reasons other than for what the drug was originally intended. With continued use of a drug, a person might find that they cannot function normally without the drug; this is a state called physical dependence. However, note that physical dependence is not in itself bad. For example, a person who has is physically dependent on insulin injections. Their body cannot work properly without it. Emotionally or mentally needing a drug to be able to function normally is called psychological dependence. When a person continues to take a psychoactive drug, they eventually need to take larger doses of the drug to get the desired effect. This process is known as building a tolerance to the drug. Drug tolerance can involve both psychological and physical factors.
    ::精神活性药物可能带来情绪和感觉的变化,而使用者可能认为这种情绪和感觉是可取的;因此,许多精神活性物质被滥用;药物滥用是指在没有医疗专业人员的咨询或指导的情况下反复使用某种药物,或出于与原用药物目的不同的原因而使用某种药物;如果继续使用一种药物,一个人可能发现它们无法正常地发挥作用;这是一种叫作身体依赖的状态;然而,注意身体依赖性本身并不坏;例如,身体依赖胰岛素注射的人,其身体不能正常工作;在情感上或精神上需要一种药物才能正常发挥作用的人,通常被称为心理上依赖性;当一个人继续服用某种精神活性药物时,他们最终需要服用更大剂量的药物才能达到预期的效果;这一过程被称为建立对药物的耐受性;药物的耐受性可能涉及心理和身体两方面的因素。

    A person who is abusing a drug may eventually lose control of their drug-taking behavior. This is partly due to the changes the drug has caused in their brain and partly due to learned drug-abuse behaviors (such as stealing and lying to get money or drugs). In the state of addiction, a drug addict’s life and activities revolve around getting more of the drug to feed their habit, even if it leads to severe consequences such as getting arrested, dropping out of school, or isolation from friends and family. In a person who is addicted to a drug, the pattern of increasing doses due to tolerance can lead to a drug overdose (also known as an OD). A drug overdose is generally considered harmful and may lead to death. Drug dependence and addiction are caused by changes in the way neurons in the CNS send and receive neurotransmitters. It is for this reason that dependency and addiction are treated as brain disorders by medical professionals.
    ::滥用毒品的人最终可能失去对吸毒行为的控制。 这部分是由于毒品在其大脑中造成的改变,部分是由于学会滥用毒品的行为(如偷窃和撒谎以获取金钱或毒品 ) 。 在吸毒的状态下,吸毒成瘾者的生活和活动围绕着获取更多药物以养活其习惯,即使这会导致诸如被捕、辍学或与朋友和家人隔绝等严重后果。 在吸毒成瘾者身上,由于容忍而增加的剂量模式可能导致吸毒过量(也称为吸毒过量 ) 。 吸毒过量通常被视为有害,可能导致死亡。 在吸毒成瘾的状态下,吸毒成瘾和吸毒成瘾是由CNS神经元发送和接收神经传递器的方式变化造成的。 正因为如此,依赖和吸毒成瘾被医学专业人士视为脑疾病。

    Several classes of psychoactive drugs are commonly abused. Stimulants, such as cocaine, nicotine, and amphetamine, increase the activity of the sympathetic nervous system, the central nervous system, or both. Stimulants generally increase heart rate, , and one's sense of alertness. Some stimulants, such as caffeine, are used medicinally to increase or maintain alertness and to counteract fatigue. High doses of stimulants can be fatal. A common source of nicotine is cigarette tobacco, which is shown in  Figure .
    ::兴奋剂,如可卡因、尼古丁和安非他明,增加了同情性神经系统、中枢神经系统或两者的活性。兴奋剂一般会增加心率、心率和警觉感。一些兴奋剂,如咖啡因,在药学上被用于增加或保持警觉和抗疲劳。高剂量的兴奋剂可能致命。尼古丁的一个常见来源是烟雾,如图6所示。

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    Cigarettes are a common source of nicotine. Nicotine is a compound that is found in the leaves of the tobacco plant. It is a potent neurotoxin for insects and was once used as an insecticide. In addition to the addictive nature of nicotine, long-term tobacco use carries significant risks of developing various cancers as well as strokes and severe cardiovascular and respiratory diseases.
    ::烟是尼古丁的常见来源。尼古丁是烟草厂叶叶中发现的化合物,是昆虫的强效神经毒素,曾被用作杀虫剂,除了尼古丁具有上瘾性外,长期吸烟还具有发展各种癌症、中风和严重心血管及呼吸道疾病的重大风险。

    Hypnotics, also known as depressants , such as alcohol, codeine, barbiturates, and benzodiazepines, generally decrease the activity of the central nervous system. Depressants slow down brain function and give a drowsy or calm feeling. However, taking too much of a depressant drug can cause dangerously slow and heart rates and may result in death. Many depressants acting on the CNS do so by increasing the activity of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), although there are many receptors that are affected by different depressants. GABA calms the activity of the CNS and promotes sleep. Drugs that stimulate the activity of this amino acid slow down brain function and cause a drowsy or calm feeling, so depressants are generally prescribed to relieve symptoms of anxiety or insomnia.
    ::催眠剂,也称为抑制剂,如酒精、可待因、巴比妥酸盐和苯并二氮杂卓,一般会减少中枢神经系统的活动,抑制剂会减慢大脑功能,产生沉睡或沉睡的感觉,但是,服用太多抑制剂可造成危险的缓慢和心率,并可能导致死亡。许多抑制剂通过增加抑制性神经中继剂伽马氨基丁酸(GABA)的活性而出现,尽管受不同抑制剂影响的受体很多。GABA使CNS的活动平静下来,促进睡眠。刺激氨基酸活动、减慢脑功能并造成沉睡的药物,导致沉睡或沉睡,因此一般会开止痛剂来缓解焦虑或失眠症状。

    Hallucinogens, also known as psychedelic drugs, such as lysergic acid diethylamide (LSD), phencyclidine (PCP), and ketamine, are psychoactive drugs that do not increase or decrease a certain feeling or emotion, but rather induce experiences, such as sensory distortions and “out-of-body experiences,” that are very different from those of ordinary consciousness. These experiences are often called trance-like states. The use of psychedelic drugs has been linked to a potential for brain damage.
    ::致幻剂,也称为精神错乱药物,如赖塞基酸二乙胺(LSD ) 、 苯环胺(PCP)和氯胺酮,是精神活性药物,不会增加或减少某种感觉或情感,而是诱发感官扭曲和“体外体验”等与普通意识完全不同的体验。 这些经历通常被称为像麻风病一样的状态。 使用精神错乱药物与脑损伤的可能性有关。

    There are many ways in which psychoactive drugs can affect the CNS. Each drug has a specific action on one or more neurotransmitters or receptors. Drugs that increase activity in particular neurotransmitter systems are called agonists. They act by increasing the synthesis of one or more neurotransmitters or reducing its reuptake from the synapses. Drugs that reduce neurotransmitter activity are called antagonists and work by interfering with synthesis or blocking postsynaptic receptors so that neurotransmitters cannot bind to them. The drug ketamine, which is used as an anesthetic and a painkiller, blocks the action of the neurotransmitter glutamate. Diacetylmorphine (heroin) enhances the action of endorphins in the brain. Different drugs also affect different parts of the brain. For example, drugs that affect breathing, such as cough suppressants, affect the brainstem to stop the coughing reflex . Painkillers (analgesics) block pain messages coming through the spinal cord from the body. In  Figure the brainstem region is blue, and the spinal cord is yellow.
    ::精神活性药物可以通过多种方式影响 CNS 。 每种药物都对一种或多种神经传递器或受体有特定行动。 增加特定神经传递器系统的活动的药物被称为刺激剂。 它们通过增加一种或多种神经传递器的合成或减少其从神经突触中重新获得的药物发挥作用。 减少神经传递活动的药物被称为对抗剂,它们通过干扰合成或阻塞后合成受体来工作,从而使神经传递器无法与它们结合。 用作麻醉剂和止痛剂的药物氯胺酮阻断了神经传递器的动作。 甲状腺突变素(海洛因)可以增强大脑内分泌素的动作。 不同的药物也会影响大脑的不同部分。 例如, 影响呼吸的药物,如咳嗽抑制剂,会影响大脑的大脑,从而阻止咳嗽反应。 止痛剂( 止痛剂) 阻断从身体脊椎带传来的痛苦信息。 在图图中,脑膜区域是蓝色的, 脊髓是黄色。

    How Addiction Happens
    ::吸毒成瘾的发生情况

    The neurobiological theory of addiction proposes that certain chemical pathways are greatly changed in the brain of an addicted person. Almost all drugs that are abused affect a certain set of brain structures in the limbic system, which is also called the "brain reward system." (see Figure ). The neurotransmitter dopamine is commonly associated with the brain reward system. Dopamine is released at synapses by neurons when a person has a pleasurable experience such as eating a favorite food or eating when very hungry. This system provides feelings of pleasure (the “reward”)and motivates a person to perform certain activities over and over again. Such mechanisms have evolved to ensure the survival of organisms .
    ::毒瘾的神经生物学理论表明,某些化学途径在瘾君子的大脑中发生了巨大变化。几乎所有被滥用的药物都会影响肢体系统中的某种脑结构,也就是“脑奖赏系统 ” ( 见图 ) 。神经转移剂多巴胺通常与大脑奖赏系统相关。多巴胺在神经元突触时被释放,因为一个人有快乐的体验,比如吃最喜欢的食物或者非常饥饿的饮食。这个系统提供快乐感( “ 奖励 ” ) , 并激励一个人一次又一次地开展某些活动。 这种机制已经演化,以确保生物的生存。

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    The limbic system (in red) includes structures in the human brain that have been linked to emotion, motivation, and emotional association with memory. The action of neurotransmitters in the limbic system is altered by addictive drugs.
    ::左肢系统(红色)包括人类大脑中与情感、动机和与记忆的情感联系相关的结构。 左肢系统中神经传递器的动作被上瘾药物改变。

    Some drugs, such as cocaine, nicotine, amphetamines, and alcohol, directly or indirectly increase the amount of dopamine in the limbic structures. The pleasurable feelings that these drugs produce trick the body into thinking that the drug is good, important for survival, and needs to be taken repeatedly. Drugs that directly affect the brain reward system are highly addictive. The stimulant nicotine, which is found in tobacco, is one such drug.
    ::有些药物,如可卡因、尼古丁、安非他明和酒精,直接或间接地增加断肢结构中的多巴胺数量。 这些药物产生的令人愉快的感情诱使身体认为该药物是好的,对生存很重要,需要反复服用。 直接影响大脑奖赏系统的药物具有高度上瘾性。 烟草中发现的兴奋剂尼古丁就是这种药物之一。

    Cocaine is an example of a psychoactive drug that is both used as a medicine and abused as a drug. Cocaine is highly addictive. It is a dopamine transporter blocker—it blocks the reuptake of dopamine by the presynaptic neuron. This action increases the amount of dopamine left in the synaptic cleft , so dopamine has a stronger effect on the postsynaptic neuron. Continued cocaine use causes a reduction in the number of dopamine receptors on the postsynaptic neuron. Eventually, the postsynaptic neuron becomes understimulated because there are fewer dopamine receptors on it to respond to dopamine. At this point, more cocaine must be taken to stimulate the postsynaptic neuron into an action potential. If a person becomes dependent on the drug, they need cocaine for their body to act normally. If a person were to stop taking the drug at this point, their body would not be able to act normally, and they would experience a range of uncomfortable and painful symptoms called withdrawal. Symptoms of withdrawal include vomiting, diarrhea, and depression.
    ::可卡因是一种精神活性药物,既被用作药物,又被滥用为药物。可卡因是高度成瘾性药物。它是一种多巴胺运输阻塞器,它阻塞了多巴胺通过先发性神经元重新服用。这一行动增加了合成神经裂痕中多巴胺的残留量,因此多巴胺对后合成神经神经有更强烈的影响。继续使用可卡因导致多巴胺受体在后合成神经元上的数量减少。最终,后合成神经元会变得低迷,因为对多巴胺的反应较少多巴胺受体。此时,必须使用更多的可卡因刺激后发性神经元的行动潜力。如果一个人依赖该药物,他们的身体需要可卡因才能正常地行动。如果一个人停止服用该药物,他们的身体将无法正常地行动,他们将经历一系列不舒适和痛苦的症状,叫做戒毒。从此时,需要用更多的可卡因刺激后发性神经元进入行动潜力。如果一个人开始依赖该药物,他们的身体需要可卡因才能正常地行动。

    Many psychoactive substances are used or abused for their mood and perception altering effects including those with accepted uses in medicine and psychiatry. Classes of drugs that are frequently abused include some of the drugs listed in  Table . Drugs that are deemed to have no medical use and a high potential for abuse are usually illegal.
    ::许多精神活性物质因其情绪和感知改变作用而被使用或滥用,包括那些在医学和精神病学中被接受用途的药物,经常被滥用的各类药物包括表中所列的一些药物。

    Not all drugs are physically addictive, but any activity that stimulates the brain reward system can lead to psychological addiction. Drugs that are most likely to cause addiction are drugs that directly stimulate the dopaminergic system like cocaine, nicotine, and amphetamines. Drugs that only indirectly stimulate the dopaminergic system, such as psychedelics, are not as likely to be addictive.
    ::并非所有药物都具有物理上瘾性,但任何刺激大脑奖赏制度的活动都可能导致心理上瘾。 最可能导致成瘾的药物是直接刺激多巴胺基体系的药物,如可卡因、尼古丁和苯丙胺。 仅间接刺激多巴胺基体系的药物,如迷幻剂,不太可能有上瘾性。

    Some Commonly Abused Drugs
    Psychoactive Drugs Effects Examples Some Common Forms or Names
    Stimulants Elevate the central nervous system and raise levels of alertness and wakefulness. Caffeine, cocaine, amphetamine, and methamphetamine. Coffee, coke, meth, and ecstasy (X).
    Hallucinogens Induce perceptual and cognitive distortions. LSD, psilocybin, mescaline, and PCP. Acid, magic mushrooms , peyote, and angel dust.
    Hypnotics Depress the CNS and induce sleep. Barbiturates, opioids (e.g. codeine, morphine, and oxycodone), benzodiazepines, and ethanol. Diazapam and alcohol.
    Analgesics Induce euphoria and reduce sensation of pain. Codeine, morphine, ketamine, heroin, phencyclidine (PCP), and tetrahydrocannabinol (THC). Horse, angel dust, cannabis, and marijuana.

        

     

    Summary
    ::摘要

    • Psychoactive drugs alter cognitive function by altering neurotransmission; stimulants, hypnotics, and hallucinogens are three common types of psychoactive drugs that are abused.
      ::精神活性药物通过改变神经传播而改变认知功能;兴奋剂、催眠剂和致幻剂是被滥用的三种常见精神活性药物。
    • Drugs include all substances that affect the body's structure or function, while medicine is a drug that is taken on a doctor's recommendation to cure or reduce the symptoms of an illness.
      ::药物包括影响身体结构或功能的所有物质,而药物是医生建议治疗或减少疾病症状的一种药物。
    • Drugs cause physical and/or psychological dependence, and addicts often form a tolerance, which can sometimes lead to a drug overdose.
      ::毒品导致身体和/或心理依赖,吸毒者往往形成一种容忍,有时可能导致吸毒过量。

    Review
    ::回顾

    1. How does a psychoactive drug affect the brain?
      ::精神活性药物如何影响大脑?
    2. What are the results of drug abuse?
      ::药物滥用有什么结果?
    3. What are the differences between stimulants, hallucinogens, hypnotics, and analgesics?
      ::兴奋剂、致幻剂、催眠剂和止痛剂之间有什么区别?